Studies of the action of the fungicides triarimol, triforine and of compounds with related mechanisms of action will be continued. The relationship of free fatty acid accumulation to phospholipid and membrane deterioration will be studied in sporidia of Ustilago maydis treated with the fungicides. Investigations will be carried out to determine whether the aforementioned fungicides bind to sterol carrier proteins. Antisporulant activity of the compounds will be investigated to determine whether interference with hormone synthesis is involved. The mechanism of antipathogenic action of the non-fungitoxic compound, tricyclazole, will be investigated. BIBLIOGRAPHIC REFERENCES: Sherald, J.L. and H.D. Sisler. 1975. Antifungal mode of action of triforine. Pestic. Biochem. Physiol. 5:477-488. Sisler, H.D. and N.N. Ragsdale. 1975 Fungicides affecting sterol metabolism in "Systemic Fungicides". (H. Lyr and C. Polter, eds.) Academic-Verlag, Berlin, pp. 101-108.